Adaptive transmission controls are, for example, known from U.S. Pat. No. 5,157,609 and German patent publication 4,136,613 as well as from the articles from xe2x80x9cAutomobiltechnische Zeitschriftxe2x80x9d 94 (1992) 9, starting at page 428 and from xe2x80x9cAutomobiltechnische Zeitschriftxe2x80x9d 95 (1993) 9, starting at page 420. In automatic transmissions, the transmission changes are, in general, determined in dependence upon the vehicle longitudinal speed and the engine load (throttle flap angle). This takes place by means of a characteristic field. In adaptive transmission control systems, the characteristic field can be adapted to the behavior of the driver (driver type), the traffic situation and/or the driving situation to which the vehicle is subjected. The transmission ratio changes are determined by means of the characteristic field. In setting the behavior of the driver, it is generally evaluated whether the driver adheres more to a driving-power orientated driving manner or more to a fuel optimized driving manner. In the evaluation of the traffic and driving situation, it can be distinguished, for example, whether the vehicle is in city traffic, ahead of or in a curve, on a hill or in overrun operation. Depending upon the evaluation of the above-mentioned points, the particular characteristic line which is suitable is selected from a number of different characteristic lines. Furthermore, a shifting of the base shifting characteristic field, as described in U.S. Pat. No. 5,857,161, can be provided.
The so-called driving situations (such as uphill travel, driving on slippery roadway (winter), driving with a cold engine (warming up) or driving in a curve) are a decisive influence on the selection of the transmission gear to be selected. This is so because, in each of these situations, there are specific characteristics which are to be considered in the selection of a transmission gear which ensure the driving safety and the driving comfort.
To recognize the traffic or driving situation to which the vehicle is subjected at a particular time, the state of the art suggests arriving at an estimate of the instantaneously present traffic and/or driving situation via different algorithms (for example, mountain recognition, curve recognition, winter operation recognition, city driving recognition and/or warm-up recognition).
Furthermore, a hierarchially structured control of the elements of the drive train of a motor vehicle is known from U.S. Pat. No. 5,351,776. The drive train includes, for example, the engine, clutch/torque convertor, transmission. A software structure for determining the transmission ratio is disclosed in U.S. Pat. No. 6,216,077 and incorporated herein by reference.
It is the object of the invention to configure the determination of individual driving or traffic situations so that the system can be adapted in an easy manner to as many different requirements as possible.
The system of the invention is for adjusting a transmission ratio in a transmission built into a motor vehicle. The system includes: at least two determination elements (FS_X(i)) for determining values based on different determination modes with the values representing individual driving situations of the motor vehicle; administration means for calling up the values from the determination elements (FS_X(i)) and storing the values; the administration means functioning to output individual ones of the values in response to a command (ACT_FS_X(i)); and, means for adjusting the transmission ratio at least in dependence on the outputted ones of the values.
The invention affords advantages with respect to expansion, functionality and the reusability as set forth below.
The number of individual determination elements, which recognize individual driving situations, is virtually unlimited. An expansion of the system by additional determination elements is easily possible because, in accordance with the invention, fixedly defined interfaces are made available by the administration means. For example, if a system, which is applied for a specific vehicle engine type, is to be expanded for another vehicle type by further determination elements, then this is relatively simple in the system according to the invention because, for a new determination element, simply a new address or a new identification code need be added to the administration means.
As mentioned, the determination of individual driving situations (for example, mountain recognition, curve recognition, winter operation recognition, city driving recognition and/or warm-up recognition) takes place in the individual determination elements. In response to the command in accordance with the invention, the determined individual values, which represent the individual driving situations of the motor vehicle, are called up. By means of an evaluation of these values, the gear selection can then determine the transmission gear to be selected. According to the invention, a separation therefore takes place between the actual evaluation of the driving situation for the gear selection and the determination of the individual driving situations in the determination means. This guarantees a high flexibility with respect to various requirements in the application to various vehicle types.
For different requirements on the transmission control in a new vehicle type, the xe2x80x9coldxe2x80x9d structure for determining the individual driving situations remains unchanged. Under some circumstances, simply new determination elements need be added or old determination elements omitted.
For the same part requirements in a different context, determination means can be exchanged simply because of the interfaces defined in accordance with the invention.
In an advantageous embodiment of the invention, it is provided that means for gear selection are provided with which the command is outputted. The subsystem comprising the administration means and the determination means is therefore a part of a total system for transmission control. The actual evaluation of the individual driving situations takes place, as a rule, in the gear selection.
Furthermore, it can be provided that, via the administration means, the determined values can be called up cyclically by the determination elements and stored. The call-up of the values takes place therefore in a pregiven sequence. It can be especially provided that the administration means calls up and stores the determined values from the determination elements at pregiven time intervals, for example, every 25 ms.
It can be provided that the administration means calls up and stores the determined values from the determination elements in response to an additional command which, for example, proceeds from the above-mentioned gear selection.
Furthermore, the administration means can be so configured that at least one determination element is not called up or stored.